Improvement in rotary steam-engines



3 She ts--Sheet 2. C. F. MURDOCK.

Improvement in Rotary Steam-Engines.

No. 130,063, PatentedJuIy30,1872.

3 Sheets--Sheet3. C. F. MURDOCK.

Improvement in.Rotary Steam-Engines.

No. 130,063, Pate nted July 30, 1872.

Wigwam. fiwl iag,

UNITED STATES PATENT OFFICE.

CHARLES F. MURDOOK, OF OASEVILLE, MICHIGAN.

IMPROVEMENT IN ROTARY STEAM-ENGINES.

Specification forming part of Letters Patent No. 130,063, dated July 30,1872.

SPECIFICATION. To all whom it may concern:

Be it known that I, OHARLEs F. MURDocK, of Oaseville, in the county ofHuron and State of Michigan, have invented certain Improvements inRotary Steam-Engines, of which the following is a specification,reference being had to the accompanying drawing.

My invention consists in a novel construction of a rotary steam-engine,as hereinafter more fully explained.

Figure 1 is a vertical section on the line 3 51 of Fig. 2. Fig. 2 is avertical section at right angles to the line of Fig. 1. Fig. 3 is a sideelevation; and Figs. 4, 5, and 6 are views of portions shown detached.

My invention consists essentially of a cylindrical revolving case,having a series of pistons or abutments arranged to slide through radialopenings therein, and to travel in an e1- liptical chamber formed byinserting an elliptical center or hub within a correspondinglyforrnedshell or case, A representing the case, 0 the revolving cylinder, e thepiston or sliding abutments, and D the center or hub, acting as a guideor cam to force the pistons e outward at the required intervals. Inconstructing my engine I first form the center or hub D by taking twosemicircular pieces and turning off their outer faces so. as to form,when. put together, a true cylinder. I then secure to their inner orflat faces pieces J, as shown in Fig. 1, these pieces extending outflush at Y the periphery and sides, and thus converting the cylinderinto an elliptical body, its diameter on its longer line being as muchgreater than its shorter diameter as the thickness of the insertedpieces J. Where these pieces J meet at the center their faces are madeto interlock, as represented in Fig. 6, whereby the pistons arefurnished a continuous bearing in passing the joint. This central hub Dis represented in the drawing as being made solid; but it may be hollow,and will be so made in large engines. It is mounted on a rectangularshaft, Y, on each side of which recesses are formed inthe segments D, inwhich recesses are placed two flat springs, k, to press the segmentsoutward. The shaftY is stationary, and serves as a support forthecenter, and is provided with two cross-arms, 1', which fit in recessesin the outer sides of the segments, at right an gles to their line ofjunction, thereby supporting and holding them in place, the segmentsresting and sliding on these arms rwhen moved at all. I then construct acylindrical case, 0, with solid or tight heads or ends, and having atubular journal, M, projecting from each end, as shown in Fig. 2, whichis mounted in suitable bearings R and made to completely inclose thecenter or hub D, the tubular journals inclosing the shaft Y and beingpacked thereon, as represented at h, Fig. 2. Through the periphery ofthis case 0 a series of slots is cut radially, and extending across itsface from side to side, in which I fit sliding pistons or abutments e,as shown in Fig. 1, one of the slides or pistons being shown detached atFig. 7. These parts being thus arranged, I then surround or inclose themin an outer case or shell, A, which, in turn, is supported on the mainframe, and has packing-glands'G, where the tubular journals M pass outthrough its sides, as shown in Fig. 2. This outer shell A is madeelliptical in the same manner and to the same extent as the center orhub D is, but of larger diameter, so as to leave a space all aroundbetween them for the pistons c with their cylinder 0 to travel in, thepistons e be" ing of such a width as to exactly fill this spacetransversely, as shown in Fig. 1. lar body of this shell A has its outeredges raised or projected radially so as to form a depression betweenthem, which, being covered by plates B, as represented in Fig. 2, leavesan annular space or chamber extending all around the shell or case A,this space being divided, by partitions w, into a series of chambers, asshown in Fig. 1. Through the periphery or annular body of this shell A aseries of opein ings or ports is cut, they being arranged at equaldistances apart on each side, as shown in Fig. 1, and being designatedby the letters a, b, c, and d. A series of slide-valves, 0, is arrangedto close these ports by sliding between the shell A and the outer platesB, these valves being all connected, by arms f, to rockshafts 17.mounted in suitable bearings upon the plates B, these rock-shafts, inturn, being connected, by arms on, to curved rods P, which are connectedand operated by a hand-lever, H, as represented in Fig. 3. The steam isad mitted to the engine upon opposite sides at the same time, it beingconveyed through pipes The annu- E in at both top and bottom, the escapesteam passing off at both sides, at right angles to the points at whichit enters, through the pipes F, as represented in Fig. 1. In thedrawing, I have represented the ports so arranged as to divide the caseA into six equal parts, there being eight ports in all-four on eachside. It will be observed, by examining Fig. 1, that the inner face ofthe shell A is recessed or cut away centrally along each alternate spacebetween the ports, thus leaving along each side of this cut-away portiona shoulder, 'r', as shown in Fig. 1, and also at the lower side of Fig.2, so that, while the pistons e are passing along past these places,they do not entirely fill the steam-space, there being an opening behindthem, through which the steam flows past the piston, and thus onward tothe next one. It will also be observed'that the ports are arranged toopen into the chambers between the shell A and the plates B, and thatthe supply and exhaust pipes connect with these chambers, the steampassing in and out through them, and serving in connection therewith tokeep the shell A jacketed with steam. The valves 0 are arranged inpairs, connected by a rod, Z, as shown in Fig. 4, and can be adjusted tofit the ports, as shown, their function being to reverse the engine whendesired.

The operation is as follows: The engine being constructed as described,and the valves set as in Fig. 1, the steam will rush in through theports a a, and, striking against the pistons 6, will cause the cylinder(J to revolve. As it moves, the steam will rush past the pistons enearest the inlet-ports, while the latter are passing from the ports ato the ports d; but as soon as the pistons reach or pass the ports d,the'pistons e fill the space between the cylinder 0 and the case A, andfrom thence on to the exhaust-ports b. On each side the steam isexerting its full force against the pistons, the steam beginning toescape from in front of the piston the moment it arrives, where it fillsthe entire space by the piston in front of it just then reaching theexhaust-port b. As each piston is in turn brought round by the cylinder0, it is shoved entirely in, or nearly so, as it passes the point V justin front of the inlet-port, and is then forced gradually outward as itpasses along until it has made a quarter revolution, after which it isdrawn grad ually inward during the next quarter of a revolution; andthis is repeated during the latter half of the revolution, thesemovements of the pistons being caused by the elliptical form of thecenter D and case A. The steam, as it escapes through the ports I), isdischarged at a reverse angle into the outer chamber, from whence itflows off through the pipes F on each side, which may be united in oneescape-pipe, F, as represented in Fig. 1, or may each dischargeseparately, as preferred. It will be seen that the ports and chambersare alike on each side, and, as the steam enters at two opposite points,it operates on both sides at the same time, and in the same manner, bywhich the friction on the center bearings is greatly lessened. Toreverse the engine the valves are moved to the opposite side, closingthe ports that were open, and opening those that were closed, when thesteam will enter at the ports 0 and escape at the ports (I. In order tocompensate for wear the center or hub D is made slightly conical, andhas a little space for being moved endwise, as shown in Fig. 2, so thatby such movement the pistons 0 can be set out against. the case A torender them steam-tight. As previously intimated the case A isconstructed on the same plan as the centerthat is to say, it is formedof two semicircular segments, turned up so as to form a true circle, andthen is made e1- liptical by inserting between their ends a piece, V, asshown in Fig. 1, the ends of the circular or segmental pieces beingunited by a bolt having a right-and-left-hand thread on its ends, whichdraws the ends of the segments tight against the pieces V, as indicatedby dotted lines in the top of Fig. 1, these bolts being loosened when itis desired to set up the pieces V to compensate for wear. It will beseen that the steam-space, and consequently the power of the engine, maybe increased at any time by simply inserting wider pieces V in the shellA, thus making it more elliptical, and increasing the size of thesteam-space between the cylinder (land the shell A, the center D beingcorrespondingly elongated by inserting thicker piece J, there being somespace left between the elongated faces of the center D and the cylinder0 for this purpose, and also to permit the pistons or Slides 6 to be ofsufficient width to allow of their being thus set out to fill the thusenlarged steam-space.

In this way I am enabled to produce a very simple, cheap,.and et'iicientrotary engine, having but few moving parts, and those of the simplestkind. 7

Having thus described my invention, what I claim is- 1. A rotarysteam-engine, consisting of a stationary elliptical center or hub, D, incombination with the rotating cylindrical case (J having the slidingpistons e, and the elliptical case A having ports and valves, arrangedsubstantially as described.

2. The case A and central hub D, each composed of two semicircularsegments, with the interposed pieces J V, whereby the capacity of theengine may be increased, substantially as set forth.

3. The case A, having recesses on its inner face between the inlet andthe next adjoining ports, for the purpose of permitting the steam toflow past the piston against the one in front while the piston ispassing along said space, as set forth. CHARLES F. MURDOOK.

Viitnesses: I

W. 0. Devon, PIIlL. T. DODGE.

